Compass for navigation purposes



Aug. 17 1926.

E. VION COMPASS FOR NAVIGATION PURPOSES 5 Sheets-Sheet 1 Filed April 1. 1924 Aug. 17 1926.

E. VION COMPASS FOR NAVIGATION PURPOSES Filed April 1 1924 5 S heets-She et 2 W L T Aug. 17, 1925. E. VlON COMPASS FOR NAVIGATION PURPOSES Filed Ab ril 1.

1924 5 Sheets-Sheet 3 Cl H ..f o

Aug. 17, 1926. 1,596,639

VE. VION v COMPASS FOR NAVIGATIQN PURPOSES Filed April 1, 1924 5 Sheets-Sheet 4 EU the mlz W1C m/Pr'ui Aug. 17 1926. 1,596,639

- E. VION COMPASS FOR NAVIGATION PURPOSES Filed April 1, 1924 5 Sheets-Sheet 5 I ll real or (M'mv 9 I W 2 Patented Aug. 17,1926.

UNITED STATES PATENT o FIcE;

EUGENE V'ION, or rams, FRANCE.

oo'nrnss rozp. NAVIGATION ronrosns Application filed April 1, 1924, serial 703,488, and in France April 10, 1823.

On board ship. and on aircraft, in order to annul semi-circular deviation due to the permanent field of the rim it has been proposed to employ a cylindrical rod, placed vertically under the centre of the'compass card and supporting two collars adapted to slide along the said-rod. These two collars carry respectively longitudinal and transverse compensating magnets and may be locked at any point on the rod,'by means of a set screw. The variation in'intensity of the compensating field is obtained by increasing or diminishing the distance of the compensating magnet from the centre of the card, by sliding the collars along the rod.

Again it has been proposed to place compensating magnets in' longitudinal and --transverse openings in thecompass casing.

In this instance there are a certain'number of longitudinal and transverse openings located at various distances-from the centre of the card. The intensity of the compensating field varies according to the opening employed, andthe number of bars inserted therein. a Again 1t has been proposed in order to annul the quadrantal deviations due to the induction of the horizontal component of v the terrestrial field in the soft iron of the rim, to employ s heres, cylinders or'bars of soft iron, place in the plane of the magnets of the card and arranged symmetrically with respect to the plane of'the latter. To-

- annul the, quadrantal deviations, it is 'necessary, a ter having suitably arranged the compensa ing masses with respect tothe axis of the'vessel, to bring them to a suitable distance from the-centre of the card, which involves a regulation by horizontaltranslation of the compensating masses.

It has been proposed to employ a bar ar ranged horizontally under the casing of the compass. After puttin thebar'in position,

the regulation is obtalned .by movmg this bar nearer to or further away from the magnets of the card in a vertical direction.

These known arrangements have the 'double disadvantage that they are inconvenient in use, and that they often require more space than 1s available, especlally on certain aircraft for use 1n war, and m particular upon fighting mono lanes. This 1s the case.

because if qua antal "deviations reach an important amount, globes-having a diameter greater than; 0.30 m., inust'be used.

\ Moreover devices, which aregive sufli- .netic field.

ciently precise results, generally require very delicate manipulation. v

The compensating devices which form the subject of the present invention, both that intended to annul the deviation due to the permanent field' of the rim and that intended to annul the deviation due to the' induced field in the iron of the rim by the horizontal component of the terrestrial field, are based upon the same novel principle.

The invention enables all vertical or horizontal movement of the attracted masses or' iron to be dispensed with, thus facilitatmg the a djustment of the compensating devlce, while at the same time diminishing its bulk.

According to the invention, each comp'ensator consists of two or more unlts- -each of which units may comprise one or more magnets or soft iron masses-such units being arranged together in pairs, with the units of each pair so mounted and intergeared that they can be adjusted in equal and opposite angular directions about an axis passing through theaxis, of the -rose or parallel thereto. 1

The regulation of the compensating parts thus only' re uires displacements in angular In Fig. 1, O is'the centre of the rose/ O-w, O-y are two axes, one of which O-y issupposed to be directed towards the front of the ship or aircraft, on whichthe compass is mounted, whilst the other O-a: is iuppiosed to'be directed towards the right an c O--h represents the horizontal component of the magnetic field, fixed with respect to the vessel, which is due'to-both the permanent field of the rim, and to the induced field in the'iron in the latter owing to the vertical component of the terrestrial mag- Itis'evident that to annill the semi-circular deviations one may either annul or its components Ov--k and 0-];,, i e zone of movement of the rose.

The device for annulling accordingi 'to tho invention, each of the fields O-h and O-'k,., comprises two parts pivotall movable either directly or through their supporting means around a pivot whlch may be common to the two elements or individual to each element, so that they can thus be set at variable angular distances apart, each' -element being constituted by a magnet or a pair of magnets.

As sh wn at Fig. 2, by meansof two magnets or two groups of magnets placed at invariable distances from the centre 0 of the rose, there may be produced in the lat- 4-4, Fig. 3.

cular'deviation.

ter fields O-h and O-k which may be equal or different, constant in magnitude but variable in direction and having a resultant Oh.

The two magnets or groups of magnets may in practice be mounted on a common support or in distinct supports, attached ornot to the casing of the'compass, connected to or independent of one another.

It is obvious that two-angles a, and a fmay be found such that the resultant of the' Fig. 4 is a sectional plan, on thelline Fig. 5 is a bottom plan.

Figs. Sand 7 show diagrammaticall two difi'erent positions of the two groups 0 compensating magnets, respectively for a zero compensating eflect for the groups of magnets F andF a maximum for the groups of magnets E and E and a compensating efi'ect comprised between zero and the maximum. Fig. 8 isatheoretical diagram inreference to the means for compensating quadrantal deviations.

Fig. 9 is another theoretical diagram, further illustrating such compensating means.

Fig. 10 is a plan, partly insection, of a practical form of apparatus for correcting quadrantal and octantal deviations. 1 1 Fig; 11 is an elevation of a portion of .the last mentioned apparatus and Fig. 12 is a view partly inelevation and partly in section of'the said apparatus.

Referring to Fig. 3 A. is a circular disc attached to the base B of: the compass box.

or in any othersuitable' position, parallel to the said base, and so that its geometrical axis passes through the, centre of the rose. This disc A. carries the? ivots C, C of the two groups of magnets y the angular diss placement of. which the component 0 -h, of the fixed field is compensated and the pivots D, D of the two groups of magnets by ular displacement of which On the pivots C, C are keyed two toothed wheels of the same'diameter (a and 0 respectively) meshing with one another, and located on the upper surface of the disc A. On the pivots D and D are keyed two toothed wheels of the same diameter (d and (1 respectively) located on the lower surface of the said disc and meshing one with the other.

The wheels 0 and c act as supports respectively for two magnets E and E or pairs of magnets, each pair being of course replacable by a single magnet. In. the same way the wheels d. and (1 act as supports for magnets or pairs of magnets F, F.

The magnets of each pair are located symmetrically with respect to the axis of the pinion forming the corresponding, pivot.

The magnets are moreover so mounted that the magnets F are parallel to the axis y-, 1

atth" sametime that the magnets F are .parallel to that axis. Similarly the magnets E- and E are at the same time parallel to the axis m-av. It'follo-ws from'the above that by means of a manipulating button a keyed on one of the axles C or C for instance on the axle "G, a simultaneous displacement of the two. groups E and E can be effected through-the same angle but in opposite directions with respect to the axis.

Similarly by means of a button keyed o'n 'one of the axles D or D the axle D for instance, a simultaneous angular displacement of the magnets orpairs of mag- -nets F, F can be-produced,through the same angle and in opposite directions with :respect to the axis y-y.

One ofthe axes, for instance y-y is set parallel to the longitudinal plane of the ship or aircraft, and is consequently parallel to,

Furthermore the four the lubbers line. poles opposite one another must be of-the same sign.

When the magnets F, F are parallel to y. 'y the position shown in Figs. 1 to-6 inclusive the north p'oles Not the magnets F being opposite the north poles N of the magnets F the field produced by them at the centre of the rose is zero, in other words thwe magnets do not exert any compensating action uponthe rose. But if, by ma nipulating the button f the wheel d is turned in the direction of the arrow 1, Fig. 5' there is produced at the centre ofthe rose, a field parallel to 0-42 and in the direction N,

andthis field increases from zero to a maximum while the wheels cl and al and the magnets F and F carried thereby turn through a. quarter of a revolution, until they are parallel to the axis v -m Fig. 7 shows diagrammatically an intermediate position of the'magnets F and F in which the latter are producing at the centre of the rose a field the two horizontal components OI-P and OH which are equal and symmetrical with respect to the -axis 00-41 these components furnishing a resultant OH along Ow.

When the angle a which the magnets F make with the axis w-a2 is equal to 90 .(the position in Fig. 6) the resultant OH rotation when the-magnets are turned paral- By "manipulating; the button 6 to turn simultaneously in opposite directions the magnets E and E there is obtained in the same way 7) a resultant Oh for the two fields Oh and Oh This re sultant will vary in magnitude between zero and a positive or negative maxim-um, and

will be in the direction Oy or Oy ac.

cording to the angle of direction and the direction of rotation.

In general by the simple manipulation of the buttons 6 and f, which is an easy and precise operation, the permanent field of the rim :is annuled in the zone occupied bythe rose, by annulling the two components of the field in succession. The compensating magnets always remain in the same plane parallel to the rose,the= compensating device occupies as little height as possible. One of the toothed wheels or both of them may be provided with pawl mechanisms to ensure the stopping of the corresponding rangement of'the magnets .E and E and and F, F a separate support might be F and F respectively on the upper and lower surfaces of the saine disc is not the only possible way of applying the principle of the invention. For each group E,. 1

r0- vided and an appropriate partof the ox or casing or any other suitable portion.of

the apparatus might be used as the support.

If the magnitude The manipulation buttons 6, f might be furnished on the part visible on the outside with lines or markings. for facilitating the adjustment of the compensating magnets, corresponding to similar markings on the disc A. These buttons might also be furnished with graduations.

.The device for compensating quadrantal deviations makes use of the same novel principles as the device for compensating semi-circular deviations just described, that is to sa the compensating masses of iron are divide into two groups, between which around a pivot passing through the centre of the rose, a variable angular separation is produced, the soft iron compensating devices being placed in the known-manner horizontally beneath-the rose.

It is obvious that .in certain types of compass, especially those for instance which enable reading to be effected from the without'inconvenience beneath the rose.'

side, the soft lron masses could be located V In the theoretical Figure 8, 0,, O reprev sents again respectively an axisdirected towards the'front of the ship or aircraft, and an axis perpendicular thereto and turned to wards the right hand side. OK represents the horizont 1 component of. the terrestrial field. O-L represents the rotary field, of

constant intensity, due-to the induction in the soft iron masses of the rim producedby the'component OK.

It is known from the theory of deviation that OL will always turn with respect to the axis Oy through an angle, which is equal to that through which the said axis turns with respect to OK. To annul the field OL there is created by means of .soft iron masses a. field OJ equal and opposite to the said field. The direction of the field OJ is regulatedjw'ith respect to that of the field OL, by regulating suitably the direction'of the axis of symmetry of soft iron compensating masses with respect; to the axis of the vessel. i

With the known compensating devices the magnitude of the field OJ is determined by moving the soft iron masses towards or away from the centre of the rose by communicating to them a vertical or horizontal movement of translation.

According to the invention, the'compensating iron is divided into two elements or groups of elements, adapted according to their distance apart and their, position with respect to the axis O y, to produce two components ()J and OJ giving a resultant OJ variable in direction and variable in magnitude between zero and a positiveor negative maximum; the said resultant annulling'of course the effects of the field OL. p

angle is denoted by 0 it .is known that the quadrantal deviation 8 may be expressed by the formula I 8=P sin 2.6+Q3' cos 2.6

where P and Q are coeflicients. If we give to these coeflicients the respective values I P=M COS a and QIM sin a then we shall obtain I 8: M sin (2 H1) In the theoretical Fig. 9, 0-K represents the horizontal component of the terrestrial field,O, the centre of the rose and R-R, a bar of soft iron placed horizontally under the-rose and at a short distance therefrom.

0 is the magnetic angle and g the angle 0,1 and 0 still denotethe axes of reference O 'turned forwards and O towards the right. r

' The bar R, R is under the influence of two substantially opposite fields, the terrestrial field and the field produced by the needles.

of the rose. By retson of the short distance of the bar from the centre of the rose, the influence of the field produced by the needles preponderates, the result is a deviation of the form 3:6! sin (ewe) The doefiicient a denotes the power of the i bar. This coeflicient depends upon the size of the barand its distance from the needles of the rose.

a sin (2 0-H?) :1 we have 0 The power of a bar of a given size placed at a determined distance (care having been taken to remove to a distance any mass caus ing disturbances) is therefore the maximum 'quadrantal deviation which it can produce and the angle ,8 denotes the position of. the bar with respect to the axes of reference,

k o Now we know that a bar of soft iron placed very close to the magnets of the rose produces an octantal deviation which canrespect to 0,7 the deviation 8 be regarded as due to a rotar field O M analogous toO L of constant intensity, but when O turns through an angle 0 with respect to O K, O-M turns through 30 with by the formula 8:6, $ll1 (40+a) the definition of?) being analogous to that It can be easily seen that a bar of the same power as the first, making with the latter an angle of 45 will produce a field of O M willbe given which will always be equal and opposite to O M whatever the value of 6.

' Once again, according to the invention, to annul the octantal produced by a single bar, this latter is replaced by two bars of equal power, the axes of which are at an angle of 45 to one another.

By these means an octantal deviation may even be, annulled which would result from the induction of the iron masses of the rim by the horizontal component of the terrestrial field.

An octantal deviation p will be produced which will annulat all] magnet angles the octantal deviation p by suitablyturning the two bars inclined to one another at any desired angle. I

Figs. 10 to 12 inclusive show respectively in 'plan, in elevation and insectional. elevation, a constructional embodiment of the compensating device, the principle of which has just been explained.

Fig. 12 shows the device under the support T of the rose, between the latter and the device for correcting the semi-circular deviations.

The two soft iron bars v v UU the simple angular separation of which is designed to produce the variable resultant equal and of opposite sign'to the deviation due to fieldproduced in the soft iron masses of the rim, are each composed of two elements or groups of elements arranged for example at 45"to one another. These elements may with this end in view, he superposed at their middle on a common axle W carried by a support T and placed on a recess of X shape,-the arms of which are in clmed at 45 to one another. The recess for elements U'and U is provided in a disc U clamped by means of screws between two other discs U and U, the disc U being provided with a toothed annulus u. The elements V and V are in the same Way lo cated in a recess in the disc V mounted on the same axle W and clamped between two provided with a toothed annulus V. i The systems of bars U, U and V, V crossing at an angle of 45 are mounted at an invariable distance from therose, for instance as shown at Fig. 12, below the supdiscs V and V, the lower disc V being port T. The toothed discs in which the said .systems of bars UU and VV at angles of 45 to one another, produce at every instant incense octantal deviations the algebraicah sum of which is zero,

The mechanism for displaying simultaneously and in opposite directions the systems U, U and V, V may comprise as shown at Figs. 10 to 12, a pinion '0 keyed on an axle mounted'in hearings in the casing Y and having a button 0 for operating it. The pinion '0 engages on the one hand the toothed annulus 'u of the support for these systems V, V and. on theother hand with a similar pinion loose on an axle 10 carried by the casing Y, and engaging with the toothed annulus u.

The vertical walls of the plates U and V may have graduations visible through an opening 3 in the casing Y On the outer wall of the casing scales may be engraved in degrees from zero to in opposite directions on each side from a com mon zero placed at Z (Fig. 11), the position of which is mzv and 3 y when these latter are parallel, in other words when the two systems U, U and V, V are superposed,

the axis mw of the lower plate correspond ing then with the axis 3 of the upper one. At this moment the compensating power of the two systems is a maximum.

'On turning the .two systems equally in opposite directions by means of the button- '0 (i. e. the system U, U- with respect to the system V, V) the compensating force is decreased progressively from this maximum until it becomes zero when the system V, V is at 90 with respect to the system U, U.

The whole casing Y and thetwo discs U U, and V, V which carry the groups or systems of irons U, U and V, V is movable on the apparatus around the axle -W on each side of the mean position through an angle of about 45 not shown being provided for holding the casing in any intermediate position,

Again, pawl or other locking mechanism may beprovided for locking the operating button of on the casing Y in any adjusted position. The milled head V might for example carry a spring embracing its axle and normally engaging by means 0 a tooth with a recess upon the casing.

What I claim ahd desire to secure by LettersPatent in the United States of America 1s 1. An apparatus for compensating the deviations of a compass for a ship or aircraft, including a' compass casing, a rose, supporting means in connection with the compass casing, pairs of compensating masses pivotally mounted on the said'supportmg means, so that they can turn in a plane parallel to the plane of the rose and move symmetricallywith'respect to and on opposite sides of the axis of the rose, and means for operating the elements of apair T so that they can be simultaneously adjusted in equal and opposite angular directions with respect to a plane of the axis of the rose.

2. An apparatus for compensating the semicircular deviations of the compass for a ship or aircraft, including a compass cas.

mentioned axis of reference and passingthrough the axis of the rose, compensating magnets carried by the said axles, the poles of the said magnets being symmetrically arranged with respect to the axes of reference,

and means for rotating the axles of each pair so that the magnets are moved in equal and opposite angular directions with respect to the axes of reference, substantially as'described. t

3. An apparatus for compensating the semicircular deviations of the compass forv a ship or aircraft, including a support carried by'the compass casing, a pair of pivots carried by the said supporting means vertical to the plane of the rose at equal distances from the axis of the rose and on an axis of reference passing through the axis .of the rose, another pairof pivots also at equal distances from the axis of the rose and on an axis of reference at right "angles to the first mentioned axis of reference and passing through the axis ofthe rose, intermeshing gear wheels mounted on the pivots of each pair, the wheels of each pair being of equal diameter, compensating magnets carried by the gear wheels, with the poles symmetrically arranged with respect to the axes of reference and means for rotating the wheels of each pair so that the magnets are movedin equal and opposite angular directions with respect to the axis of reference,

substantially as. described.

4:. In apparatus of thetype described, the combination with means 'for compensating semicircular deviations,"of means for compensating quadrantal and octantal deviations, such means including two systems of soft iron bars arranged in X formation, both systems being mounted so that they can turn pivotally about the axis .of the rose and symmetrically with respect to two rectangularaxes of reference through the axis of the rose and in a plane parallel to the rose, and means for rotating the said systems in equal and opposite angular directions for the purposes set forth.

In witness whereof I alfix my signature.

EUGENE VION. 

